Messages in this thread | | | Subject | Re: [PATCH 00/23] per device dirty throttling -v8 | From | Brice Figureau <> | Date | Tue, 14 Aug 2007 09:59:35 +0200 |
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On Tue, 2007-08-14 at 04:25 +0200, Andi Kleen wrote: > On Tue, Aug 14, 2007 at 11:44:56AM +1000, Stewart Smith wrote: > > > Since the database fits in RAM, the only kind of access Mysql is doing > > > is writing to the innodb log, the mysql binlog and finally to the innodb > > > database files. > > > There are certainly a whole lot of fsync'ing happening. > > > > yes. Keep in mind that the binlog grows in file size too... so this has > > to sync all the metadata as well (ick, i know).
Back in the first days of my original bug report I moved the binlogs to another disk and it didn't change anything to my issue.
On Tue, 2007-08-14 at 04:25 +0200, Andi Kleen wrote: > It might be an interesting experiment to see if it still happens > with the file system remounted as ext2. ext2 has a much more > benign fsync than ext3.
Is it possible to perform a live remount of the fs on ext2 ?
Beside that, the RAID card has a battery backed RAM in write-back mode, I was told that fsync don't really hurt in this case (moreover the fs is mounted in journal=writeback mode).
I'll post soon blktrace files in the original bug report, this will show exactly what is the disk workload in the baseline case _and_ in the underload atypical case. Maybe that will help to shed some lights on the issue?
Anyway, thanks, -- Brice Figureau <brice+lklm@daysofwonder.com>
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